The bow hunting of big game animals is increasing in popularity in the United States. White-tailed deer, mule deer, elk, antelope, and bear are only a few of the species currently being hunted. State-of-the-art hunting arrows typically have a hollow fiberglass or aluminum shaft and are provided with a removable and interchangeable tip, or "broadhead". The type, size, weight, etc., of a broadhead may be changed depending upon the animal hunted, the weather conditions, the terrain, etc. Such arrows are quite expensive, typically ranging in price from $5.00 to $7.00.
Two problems that are common with bow hunters are: (1) locating the arrow resulting from a missed shot, and (2) locating the injured animal (if an immediate kill is not made) resulting from a successful shot. Even the best of hunters miss their target about 20-25% of the time, and less experienced hunters even more. When shooting from a range of 50-100 yards, it is not uncommon to lose the arrows resulting from errant shots. A typical hunter may lose 10-20 arrows per year, resulting in substantial financial loss. Even more importantly, however, the loss of game resulting from successful shots is significant. While it is possible to drop a smaller animal immediately with a well-placed shot, larger animals such as deer, elk, bear, etc., are seldom instantly killed by an arrow. Whether the arrow passes completely through the animal or remains imbedded therein, the animal may run from a few hundred yards to two miles before either dying or resting.
Hunting arrows have been developed which contain transmitters, enabling the bow hunter with a receiving unit to locate either the arrow after an errant snot, or the quarry after a successful shot, presuming the arrow remains imbedded in the quarry. For instance, U.S. Pat. No. 4,749,198 discloses a battery-powered transmitter located behind the arrow tip and having an antenna extending through the shaft of the arrow. The transmitter is activated by rotation of the arrow tip by the archer prior to shooting. The arrow of U.S. Pat. No. 4,421,319 includes an audible signal device in the nock of the arrow. The switch on this device is located on the nock of the arrow and is an on-off pushbutton-activated by the archer. U.S. Pat. No. 4,675,683 discloses a transmitter positioned intermediate the arrowhead and the nock of a hunting arrow. The transmitter is provided as an extension of the arrow between the main body of the arrow and the arrowhead. The shaft of the arrow serves as the antenna for the transmitter and the transmitter remains with the arrow at all times. The transmitter is turned on by removing a pin from the arrow shaft which in turn allows a switch to close and activate the transmitter. U.S. Pat. No. 4,704,612 issued Nov. 3, 1987, discloses a radio frequency transmitting arrow containing a power supply, an inertia-activation switch, and a directional responsive radio receiver. The inertia switch uses a torsion spring to contact a conductor during arrow acceleration only, as it leaves the bow, thereby activating the transmitter.
The foregoing patents have addressed the problem of errant shots and successful shots wherein the arrow remains imbedded in the quarry, but other problems have not been addressed. It should be noted that in three of the four of the above cases transmitter activation requires manual operation of a switch by the archer. There are drawbacks to this type of switch action. First, it takes perhaps one or two seconds to hold the arrow and turn, pull, or push the switch, which delays the firing at a critical time. Second, the archer may not shoot the arrow but remove it and replace it in the quiver and fail to turn off the switch, or the switch may be inadvertently activated in the quiver, during transport. In both cases, the result may be a dead battery and a non-functioning transmitter. Finally, in the event the contact does not close during acceleration, i.e. shooting the arrow, the transmitter again will not energize. It is the purpose of this invention to provide an inertia switch for an arrow that activates during acceleration and deceleration, as the arrow hits the target or ground, as the case may be. Actuation causes the radio transmitter to commence signal generation that is located by a direction-responsive receiver.